Abstract:Posttraumatic stress disorder (PTSD) is one of the most commonly diagnosed psychiatric disorders in the United States and has been linked to suicidal thoughts and behaviors, yet the role of a PTSD diagnosis on functional impairment among suicidal individuals remains unknown. This study examined the association between PTSD status and functional impairment among military psychiatric inpatients admitted for acute suicide risk (N = 166) with a lifetime history of at least one suicide attempt. Measures of functionality included: (1) alcohol use; (2) sleep quality; (3) social problem-solving; and (4) work and social adjustment. Thirty-eight percent of the sample met criteria for PTSD. Women were more likely than men to meet criteria for PTSD (p = 0.007), and participants who met PTSD criteria had significantly more psychiatric diagnoses (p < 0.001). Service members who met PTSD criteria reported more disturbed sleep (p = 0.003) and greater difficulties with work and social adjustment (p = 0.004) than those who did not meet PTSD criteria. However, functionality measures were not significantly associated with PTSD status after controlling for gender and psychiatric comorbidity. Gender and number of psychiatric comorbidities other than PTSD were significant predictors of PTSD in logistic regression models across four functionality measures. Future studies should assess the additive or mediating effect of psychiatric comorbidities in the association between impaired functioning and PTSD. Clinicians are encouraged to assess and address functionality during treatment with suicidal individuals, paying particular attention to individuals with multiple psychiatric diagnoses.